Question

On heating a rod, its length increases. On what factors does the increase in the length depend on?

• A. The material of the rod
• B. The initial length of the rod
• C. The rise in the rod's temperature
• D. The cross sectional area of the rod

Answer 1

Answer: (A), (B), (C)

The correct options are
A The material of the rod
B The initial length of the rod
C The rise in the rod's temperature

The increase in the length of a solid object depends on:

• How much the temperature is increased? The more the rise in temperature, the more the linear expansion.
• The initial dimensions (length) of the rod
• The material of the rod

Each material has its own way of expanding due to heat. This is given by a parameter called the coefficient of linear thermal expansion. The relation is given by:
${\text{l}}_{\text{T}}-{\text{l}}_{\text{0}}={\text{l}}_{\text{0}}\alpha \Delta \text{T}$, where ${\text{l}}_{\text{0}}$ is the initial length of the object, ${\text{l}}_{\text{T}}$ is the final length of the object, $\Delta \text{T}$ is the rise in the temperature, and $\alpha$ is the coefficient of linear thermal expansion of the material of the object.